This trial was carried out from November 2001 to November 2002, aiming at the evaluation of the effects of nitrogen fertilization upon the tiller demography and forage biomass in Brachiaria decumbens cv. Basilisk pastures fertilized with nitrogen and subjected to the same grazing height. The treatments consisted of four nitrogen rates (75, 150, 225 and 300 kg/ha.yr.) applied before the beginning of the experimental evaluations, which were performed during the Summer, Fall, Winter and Spring, 2002. A completely randomized block experimental design was used with two replications. Seasons and nitrogen rates affected grass tiller population density and forage biomass. The population density of alive and vegetative tillers increased linearly, while that of the dead tillers decreased linearly with the N rates. Forage biomass increased linearly with nitrogen fertilization, whereas the population density of reproductive tillers were not affected by nitrogen fertilization. The alive tiller population density, vegetative and reproductive, leaf biomass, stem and green matter of the Brachiaria decumbens varied among the seasons, with lower values in Winter.
nitrogen fertilization; forage biomass; Brachiaria decumbens; forage; tiller; grazing
